Take a look at the Other Bets piece of Alphabet, and it's a very different story.

Combining all the units, which include Nest thermostats, fiber for high-speed Internet, health-tech division Verily and autonomous vehicles, revenue equaled $197 million, or less than 1 percent of Alphabet's sales.

Mizuho Securities analyst Neil Doshi estimates the value of Other Bets at $7 a share, also less than 1 percent of the company's $817.35 stock price at Thursday's close.

Porat made clear that most of these projects are pre-revenue, and that the key thing to look at is progress. For example, autonomous cars have now driven over 2 million miles and are now being tested in four cities, "enabling us to experience varied weather and driving conditions," she said.

But problems within Alphabet's side projects go well beyond money.

Top executives have been fleeing, leaving Alphabet without many of the visionaries who were tapped to turn moonshots into eventual reality.

Nest founder Tony Fadell left in June, and Chris Urmson, the technology chief behind self-driving cars, departed in August. That month, Bill Maris, who founded and led the company's start-up investing arm GV, stepped aside.

Most recently and perhaps most alarmingly, Google Fiber chief Craig Barrat announced his resignation this week. Barrat, who has a PhD in electrical engineering from Stanford University and holds 34 patents, is the type of executive that was supposed to thrive under the Alphabet structure.

In his 2015 founders letter announcing Alphabet's creation, CEO Larry Page listed seven things he was excited about, including "empowering great entrepreneurs and companies to flourish."

Along with Barrat's exit, Alphabet also said that it's slowing the rollout of fiber. The wireless technology is currently available in 12 cities, with four coming online in the third quarter. Porat said the company is "pausing for now our work in eight cities where we've been in exploratory discussions."

Alphabet investors today aren't the least bit concerned. The stock climbed another 1 percent on Friday and is up 12 percent over the past 12 months. It reached a record earlier this week.

But this idea that the Google cash cow will indefinitely fund science experiments is now being tested. Even though Alphabet isn't publicly breaking out each unit's financials, the company is closely watching the overall cost structure.

"Disciplined cost allocation across core Google and Other Bets, sound capital allocation and compelling valuation keep us positive," wrote Youssef Squali, an analyst at Cantor Fitzgerald, in a report on Thursday after the results.

He estimates that revenue growth among Other Bets will slow every year through 2022, from 70 percent in 2016 to 11 percent in six years.

Wall Street will likely give Alphabet plenty of latitude to fund those businesses as long as the costs remain immaterial. But conquering autonomous driving, aging, high-speed internet access and drone delivery will require a big combination of money and patience.

The hefty turnover at Alphabet suggests that may be a difficult formula to get right.